“The Wolfenstein Challenge” – “Partisans” [2nd campaign, 3rd mission]

Problem: When a caravan appears, Wolfenstein doesn't attack it! I click, but no actions are performed. Only movement is consumed... Has anyone else experienced this? (This only happens on HoF, not on the original game or in some single-player maps (School and, I think, Battle of the Plains)... castles and caravans are not attacked in these maps...)